Table 4-2. Troubleshooting-Continued

TM 10-3930-632-12

Table 4-2. Troubleshooting-Continued

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

ELECTRICAL SYSTEM

1. STARTING MOTOR CRANKS ENGINE SLOWLY.

Step 1. Check grade of oil being used.

Change oil to proper grade.

Step 2. Test battery for weak condition.

Replace battery.

Step 3. Check for shorted battery cell.

Replace battery.

Step 4. Inspect battery posts for loose connections and corrosion.

Clean and tighten terminals and cables.

Step 5. Test starter motor (para 4-33, c).

Replace starter motor (para 4-33, d).

2. STARTING MOTOR DOES NOT CRANK ENGINE.

Step 1. Check for too heavy engine oil.

Change to proper grade of oil.

Step 2. Check for defective solenoid, cables or starter motor; loose connections.

Replace defective starter motor (para 4-33) or cables. Tighten connections.

Step 3. Check for jammed condition of starter motor pinion and ring gear.

Free-up pinion or replace starter motor (para 4-33).

Step 4. Check starter relay.

Replace starter relay (fig. 4-50).

Step 5. Check for faulty ignition switch.

Replace defective switch (para 4-22).

Step 6. Check for faulty neutral starting switch.

Replace faulty switch.

2.1. STARTING MOTOR ENGAGES WITH ENGINE RUNNING.

Step 1. Check ignition ballast resistor which is mounted on the firewall and connected to the green wire from terminal 4 of

voltage regulator. Ohmmeter reading across resistor terminals should be 15 ohms 10%.

Replace defective resistor.

Step 2. Check starter relay circuit. With engine running, ohmmeter should read open between terminals 1 and 2.

Replace defective relay.

3. NO ALTERNATOR OUTPUT

Step 1. Test for defective voltage regulator.

Adjust or replace regulator.

Step 2. Test alternator (para 4-31).

Replace alternator.

4. LOW OR FLUCTUATING ALTERNATOR OUTPUT

Step 1. Check for loose fan belt.

Adjust belt (para 4-55).

Step 2. Inspect for loose or dirty electrical connections.

Clean and tighten connections.

Step 3. Test for defective alternator.

Replace defective alternator (para 4-31).

Step 4. Test voltage regulator.

Adjust or replace voltage regulator (para 4-32).

5. EXCESSIVE ALTERNATOR OUTPUT.

Step 1. Test alternator (para 4-31).

Replace defective alternator.

Step 2. Test voltage regulator.

Adjust or replace voltage regulator (para 4-31).

6. EXCESSIVE ALTERNATOR NOISE.

Step 1. Check for loose pulley or mounting.

Tighten loose parts.

Step 2. Inspect for defective bearings or armature rubbing.

Replace alternator.

7. BATTERY DISCHARGED.

Step 1. Check electrolyte level.

Fill with distilled water to above battery plates.

Step 2. Inspect for short in battery cell.

Replace battery.

Step 2. Inspect battery connections for loose, dirty or corroded terminals.

Clean and tighten cables; replace parts as required.

Change 1 4-10